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<br />GENERAL WATER-QUALITY CHARACTERISTICS OF STREAMS
<br />
<br />Water quality of Fountain and Monument Creeks is affected by many natural
<br />and manmade factors. Some of the general water-quality characteristics of the
<br />streams can be described using information about water temperature, specific
<br />conductance, pH, BODs, dissolved oxygen, and suspended solids,
<br />
<br />Water temperature is important because it affects the usefulness of water
<br />for many purposes and partially controls physical, chemical, and biological
<br />processes, Temperature affects the waste-assimilation capacity and, there-
<br />fore, the aesthetic and sanitary qualities of water, Increased temperature
<br />accelerates the biodegradation of organic material in overlying water and in
<br />bottom deposits, thus increasing dissolved-oxygen demand (D,S, Environmental
<br />Protection Agency, 1976, p, 220),
<br />
<br />Specific conductance is an indicator of general water quality because it
<br />is directly related to the concentration of dissolved solids in the water; as
<br />dissolved solids increase, specific conductance increases, In the study area,
<br />mountain streams have relatively small specific conductance because the
<br />streams are in contact with igneous and metamorphic rocks that resist chemical
<br />weathering, In contrast, streams of the plains are in contact with sedi-
<br />mentary rocks that frequently contain soluble minerals, thereby resulting in
<br />relatively large specific conductance, Specific conductance of streams also
<br />is affected by man-related activities, such as irrigation and wastewater
<br />treatment, as well as by soluble substances that enter the stream from runoff,
<br />
<br />The pH is a measure of the hydrogen-ion activity and is important in
<br />water-quality investigations because solubility of many chemical constituents,
<br />including trace elements, and the biological activity of many organisms in
<br />water are pH dependent, Thus, pH is an important factor in controlling con-
<br />centrations of chemical constituents and populations of organisms in the
<br />water, The pH also may affect the suitability of water for various Uses, A
<br />pH range of 6.5 to 9.0 is the numeric standard set by the Colorado Department
<br />of Health (1982) for Fountain and Monument Creeks,
<br />
<br />The BODs represents the quantity of dissolved oxygen required by orga-
<br />nisms ,in the stream for aerobic biochemical digestion of organic matter in
<br />water (Klein and Bingham, 1975, p, 5) and is a useful way of expressing
<br />stream-pollution loads, The rate of biochemical-oxidation reactions are
<br />dependent on water temperature, microbial population, and waste type, The
<br />BODs analysis is performed in a laboratory at a constant temperature of 20 oC.
<br />The BODs is calculated from the dissolved-oxygen depletion that occurs over a
<br />5-day incubation period,
<br />
<br />Dissolved oxygen is another constituent of interest in water-quality
<br />investigations, The dissolved-oxygen concentration in water is inversely
<br />related to water temperature and is affected by photosyuthesis, respiration,
<br />physical interaction of the water with the atmosphere (aeration), and waste
<br />loads. It generally has been considered significant in evaluating the aes-
<br />thetic qualities of water as well as for maintaining fish and other aquatic
<br />life, Therefore, the Colorado Department of Health (1982) established a
<br />minimum standard of 6.0 mg/L for Upper Fountain Creek and 5,0 mg/L for Lower
<br />Fountain Creek, Upper Monument Creek, and Lower Monument Creek,
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